C++ Program to find area of square using constructor

Program

#include <iostream>
#include<math.h>
#define PI 3.141
using namespace std;
class AreaSquare
{
  private:
    float area;
  public:
    AreaSquare(float side)
    {
        area = pow(side, 2);
    }
    void display()
    {
        cout << "Area:\t" << area << endl;
    }
};
int main()
{
    cout << "Enter value of side:\t";
    float side;
    cin >> side;
    AreaSquare area(side);
    area.display();
    return 0;
}

Output

Enter value of side:    4.2
Area:   17.64